<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .one,.two{
            color:red;
            font-size:30px;
        }
        
    </style>
</head>
<body>
    <p class="one">这是一个P标签</p>
    <h3 class="two">这是一个h3标签</h3>
</body>
</html>